It's hard to imagine the bay area going the same way as Detroit, if only for the fact that it has excellent geographic advantages. It's one of America's biggest Pacific shipping ports, and having access to the Asian markets will always be a huge strategic advantage. On top of that the very stable Mediterranean climate will always be a draw for Americans looking to live somewhere that's not too hot and not too cold.

Besides, many of the current problems of the bay area could be solved by building denser housing and better public transportation. The whole region would be improved if so many of the NIMBYs weren't opposed to "Manhattanization".